Carbonization of wool



Dec. 18, 1934. H. b. GORDON E'r Al. l 1,984,794

CARBONI ZATION OF WOOL Filed May 1l. 1953 Patented Dec. 18, 1934 UNITED STATES Howard D. Gordon and IWilliam W. Gordon, Hazardville, Conn.

Application May 11, 1933, Serial No. 670,500

10 Claims.

This invention relates to improvements in the treatment of raw or scoured wool for the removal of foreign substances of vegetable origin therefrom. More particularly, it relates to improve- 5 ments in the production of an improved stable high-grade wool from raw or scoured wool by a process involving carbonization of the extraneous or foreign substances of vegetable origin by the action of a gaseous acid reagent.

Wool in its natural state invariably contains a substantial quantity of foreign matter of vegetable origin such as burrs or shives which cling tenaciously to the woolen fibers. Many processes have been proposed for removing such foreign substances of vegetable-origin involving carbonization of the foreign vegetable matter by the action of an acid reagent applied either in the gaseous or in the liquid state.

That type of process in which the acid reagent is applied in a gaseous state is known as the dry process, while those processes in which the acid reagent is applied in the liquid state are known as wet carbonization processes.v Both types of carbonization processes have been appliedv extensively in the reclamation of wool from woolen fabrics, clippings, rags, carpets, etc., aswell as in the treatment of inferior grades of raw wool where the color and the ber strength of the treated wool are not of primary importance.

Various proposals likewise have been made for treating the better grades of raw wool for the production of light color high-grade woolen bers free from foreign matter of vegetable origin by processes involving carbonization of the vegetable matter both by the dry process and the wet process, but such processes have not been successful. The resultant woolen product of such proposed processes has always been of an inferior grade due either to discoloration of the woolen fibers, to depreciated strength of the woolen flcarbonization processes bers, or to the fact that the treated wool is harsh (or what is known as having a harsh handle) instead of soft (or having a soft handle). Moreover, wool that has been treated by many of the heretofore proposed has been unstable to the extent that if it is permitted to contact with moist air for any appreciable length of time the fiber strength, is

materially decreased and the wool becomes corrosive `so that it attacks and corrodes metal equipment with which it cornes in contact during combing, spinning or weaving. However, the carbonized wools are -superior to well scoured raw wool in one respect, namely, the absorptive properties. of the woolen fibers are improved and,l

custom, in the treatment the bers are therefore more receptive to dyes so that a materially kless amount of dye is required. Because of the undesirableproperties of wool which has been subjected to any of the carbonizing treatments heretofore known, it is still the of the better grades of raw wool for the production of high grade woolen products, to remove the foreign matter of vegetable origin manually.

By the process of the present invention the l0 foreign matter of vegetable origin is carbonized sufficiently to permit its complete removel by a gaseous anhydrous acid reagent, and an improved high-grade woolen product is produced which is free from discoloration, which possesses the desirable absorptive and dyeing properties characteristic of carbonized wools, and which retains substantially the full fiber strength of the virgin raw wool. Moreover, wool treated by the process of the present invention has a high luster or sheen, is soft, is not corrosive and is stable in that it fiber strength will not depreciate and it will not become corrosive even though subjected to moist air for prolonged periods of time in storage.

In accordance with the process of the present invention the raw well scoured wool is preheated and substantially dehydrated. It is then subjected, at moderately elevated temperatures, to the action of a gaseous acid reagent, preferably hydrochloric acid gas, in the absence of moisture for a period of time sufcient to convert the foreign matter of vegetable origin to a, veryl brittle state. In the usual carbonization process carbonization ,is completed to the.extent that the vegetable matter is completely charred and black. We have found that the vegetable matter may be reduced to a dry brittle state in -which it may be readily crushed and dusted from the woolen fibers without carrying the carbonization to the extent that the Vegetable matter is charred or dark in color. This milder carbonization action requires less time than complete carbonization, thereby increasing the capacity of the carbonizing equipment. Moreover, as the result of the milder carbonizing a'ction as well as of the exclusion of moisture the fiber strength of the wool is not impaired.

When carbonization has proceeded to the desired extent the 4gaseous acid reagent is neutralized with a gaseous alkaline agent, such as anhydrous ammonia, while still carefully excluding all traces of moisture. The presence 0f moisture prior to neutralization reduces the strength of the woolen fibers and causes discoloration of the Wool, particularly when carbonization is effected in an apparatus embodying metal parts that are attacked by the action of the gaseous acid reagent in the presence of moisture.

The neutralized dry wool while still warm is then passed between uted crushing rolls which reduce the partially carbonized vegetable matter to a ne dry dust. The pulverized vegetable matter is then dusted from the woolen fibers and the wool free from vegetable matter is then Washed with a dilute aqueous alkaline solution, preferably dilute aqua ammonia. This washing removes all traces of salts such as ammonium chloride that may be held in the interstices of the woolen fibers and which later may hydrolize on exposure to moist air. Also, the aqueous .alkaline washing treatment neutralizes any trace of hydrochloric acid gas that may be adsorbed in the woolen bers and which may not have been completely neutralized by the action of the dry gaseous neutralizing agent.

After the aqueous alkaline bath the Wool is subjected to a final washing or rinsing in fresh `water followed by drying after which it may be stored or immediately manufactured into highgrade woolen yarns or fabrics. With some Wools it is desirable to wash the wool with a soap solution after'its removal from the aqueous alkaline bath and before it is subjected to the nal fresh water rinsing treatment.

In order to obtain the best color it is desirable that the original raw wool be well scoured before the carbonizing treatment so that its content of animal greases lis reduced to 1A; per cent., or less.

The invention will be further described in connection with the drawing which conventionally illustrates one arrangement of apparatus adapted to carry out the process of the present invention, although it will be understood that this further description is for the purpose of illustration and that the invention is not limited thereto.

Figure l is a conventional illustration in elevation and partly in section of one arrangement of apparatus suitable for carrying out the process of the present invention.

Figure 2 is a section of the carbonizing chamber illustrated in Figure 1 along the line 2--2.

Referring to Figure 1 of the drawing, the assembly consists essentially of a drier conventionally illustrated 1, a carbonizing chamber 2 provided with means for supplying an anhydrous acid gas and an anhydrous alkaline gas comprising a gas generator 3 and the anhydrous ammonium receptacle 4 respectively, a vacuum pump 5, a Crusher and duster conventionally illustrated at 6, a plurality of washing devices conventionally illustrated at 7 and 8, together with suitable means for transmitting the wool from one part of the equipment 4to other parts, and means for drying the gases and for protecting the vacuum pump from the corrosive action of the gaseous reagents.

The form of carbonizing chamber illustrated in the drawing consists of a steel chamber 9 (see Fig. 2) the interior of which is protected by a lining 10 of acid resistant cement and an inner lining 11 of acid-proof brick. The chamber is provided with a removable head 12.which may be cast iron or any suitable material not attacked by the gaseous acid reagents in an anhydrous state. Within the chamber 2 is arrangeda perforate drum 13 mounted on rollers 14. This drum is provided at one end with a door 15 which may be positioned at the bottom as shown at 15 or at the top as shown at 15a merely by rotating the drum on the rollers 14. The carbonizing chamber 2 also is provided with steam-heating coils 16 and should be suitably insulated on the exterior to reduce heat losses. A plurality of perforated inlet pipes 17 are arranged to admit and distribute the gaseous acid and alkaline reagents. Al temperature indicating device is shown at 18. The wool may be transferred from one piece of equipment to another in any desired manner. However, in the dry state it advantageously may be transferred through relatively large diameter conduits by blowers.

In the operation of the illustrated apparatus, raw wool which normally contains 14 to 18 per cent. of moisture rst is passed through a customary form of drier 1. In drier 1 the wool is heated by a stream of dry air so as to reduce the moisture content to a very low value, preferably less than 5%. The dry wool at a temperature of 80-90 F. is withdrawn from the drier by the blower 19 and is discharged via conduit 20 through the opening 15a in the upper position into the perforate drum 13 in the carbonizing chamber 2. heated at all times so as to keep it dry. The chamber 2 then is closed With the head l2 and the chamber evacuated by the vacuum pump 5. Before admitting the gaseous acid treating reagent it is desirable to reduce the pressure in the carbonizing chamber to approximately 1.5 inches of mercury absolute or less. At this low pressure remaining traces of moisture are removed from the moderately heated wool. Likewise the removal of the major portion of the air prevents dilution of the gaseous acid treating reagent.

As soon as the carbonizing chamber has been suiciently evacuated, as indicated by the pressure-vacuum gauge 21, warm dry hydrochloricl acid gas is admitted through valve 22. The Warm dry hydrochloric acid gas may be secured from any source. However, we have shown a generator 3 mounted in a suitable furnace setting 23 which is adapted to generate hydrochloric acid gas by the action of sulphuric acid on sodium chloride or ordinary salt. Sulphuric acid may be supplied to generator 3 as required from container 24. In the event that it is desired to operate the generator under a substantial pressure, the sulphuric acid may be forced into the generator by supplying high pressure air to the top of receptacle 24 through connection 25. The hydrochloric acid gas from the generator 3 is passed through a drier 26 containing a suitable drying agent such as concentrated sulphuric acid. A trap or separator 27 may advantageously be provided to separate from the gaseous treating .reagent any liquid matter that may be mechanically entrained in the gas from the drier 26. A temperature within the carbonizing chamber of about 140 F. may be maintained during the acid treatment by means of the steam-heating coils 16.

'I'he length of time required to effect the requisite carbonization of the vegetable matter contained in the wool will vary with the size and character of the particles of vegetable matter and with the pressure and temperature prevailing in the carbonizing chamber during the acid treatment. At approximately atmospheric pressure and at a temperature of about 140 F. the

carbonizing action of the hydrochloric acid normally will be completed sufficiently to permit ready and complete pulverization of the vegetable matter in a period of 25 to 40 minutes. If the particles of vegetable matter contained in the wool are unusually large it may be necessary to continue the acid treatment for an hour or slightly longer. The duration of the acid treatment may be determined by removing and observing a sample of the wool being treated. For this purpose .a removable sampling device 28 is provided in the head 12. This device extends through the head 12 and is arranged to submit a sample of the wool being treated to the conditions prevailing in the carbonizing chamber. The acid treatment should be discontinued before the vegetable matter is completely charred and blackened.- With higher pressures in the carbonizing chamber the duration of the acid treatment may be appreciably reduced. To this end the pressure in the carbonizing chamber during the acid treatment may be increased to 200 pounds per square inch or more if desired.

When the action of the gaseous acid reagent .has proceeded to the desired extent the major portion of the hydrochloric acid gas is withdrawn through connection 29. The gas may be discharged through branch connection 30 to another carbonizing chamber which previously has been evacuated, or it may be drawn by the vacuum pump 5 directly through a plurality of scrubbers 31-and 32 adapted to neutralize the acid gas sopas to prevent corrosion of the vacuum pump. In the scrubbers 31 and 32 the gas is scrubbed with an alkaline neutralizing reagent, such as lime water or a solution of caustic soda We find it desirable to introduce lime water directly into and countercurrent to the'stream oi gas entering the scrubbers through connections 33 and 34. Care should be taken to prevent moisture from the scrubbers from enter-` ing the carbonizing chamber in the event of failure of the vacuum pump 5 and for this purpose it is desirable to provide a check valve 35 in line 25.

` opening valve 36. This neutralizes the remaining hydrochloric acid. During this neutralize.u tion the operation of the vacuum pump 5 is continued and the major portion of the nely divided ammonium chloride formed is carried out oi the carbonizing chamber by mechanical entrainment in the form of a mist. It is not 4 necessary to remove any appreciable amount of the acid gas from the carbonizing chamber before the alkaline neutralizing gas is introduced thereto. However, such acid gas as is removed before neutralization is available for use in a subsequent carbonizing operation. Moreover, removal of the greater portion of the hydrochloric acid gas before neutralization reduces the amount of ammonia gas required as well as the amount of ammonium chloride which will precipitate in 4the interstices of the woolen fibers. It may even be advantageous to flush the carbonizing chamber with a neutral or inert gas and again evacuate it before vsupplying the alkaline reagent. However, care should be taken to dry such a neutral or inert flushing medium.-

After the acid gashas been neutralized, the

lwashing device 8.

carbonizing chamber is ope/ned by removing the head 12. The telescopic conduit 37 is extended through the opening l5 in the drum 13 and the dry treated wool is removed by the blower 38. The dry treated wool while still hot then is passed through the usual iiuted crushing rolls and dusting apparatus, conventionally illustrated at 6, which function to crush the carbonized vegetable matter and dust it from the woolen bers.

The treated wool at this stage still contains some ammonium chloride in the interstices of the woolen fibers. Possibly it also may contain minute particles of hydrochloric acid gas adsorbed in the interstices of the woolen bers which have not been completely neutralized by the action of the gaseous alkaline reagent. In any event the wool at this stage is harsh and if exposed to moist air in storage the ber strength depreciates and the wool becomes corrosive to metal. Accordingly, we subject the wool to a washing treatment with a dilute aqueous alkaline solution, for example a dilute aqueous alkaline solution of ammonia or soda in the washer 7. On leaving the washer 'I the wool is passed through the pressure rolls 39 and thereafter it is given a final fresh water rinse in a similar The washed wool then .is passed through a conventional drier (not shown) and the dry wool then may be stored or immediately woven into high-grade woolen yarns or fabrics.

With some wools it is desirable to subject the product from the washer 7 to an intermediate treatment in which the wool is washed with a soap solution before subjecting it to the rlnal fresh water rinsing treatment. If this is desireda third washing device similar to the Washers '7 and 8 may be interposed between the two washers illustrated in the drawing. In the washer 7 a solution of approximately V2 gallon of ordinary aqua ammonia to approximately 200 gallons of water will give satisfactory results, and this -bath advantageously is maintained at a temperature of about 100 to 120 F. The duration of the aqueous alkaline bath is controlled so that the wool emerging from the rollers 29 will be neutral as shown by the application of acid and alkaline indicators thereto from time to time.

It will be appreciated of course that any number of carbonizingI chambers may be operated with a single set of driers, washers and gas generating equipment, and that the form of apparatus employed to carry out the process of the in- 4vention may be varied widely, the apparatus shown merely being illustrative of one form of apparatus that has been found to give satisfactory results.

We claim:

l. The improvement in the treatment of raw wool for the removal of foreign matter of vegetable origin which. comprises subjecting the wool to the action of a dry gaseous acid carbonizing reagent at a moderately elevated temperature l to the action of dry hydrohloric acid gas at a moderately elevated temperature while excluding moisture therefrom, neutralizing the hydrochloric acid gas with anhydrous aonia while continuing the exclusion of moisture, crushing and dusting the carbonized foreign vegetable matter from the Wool bers and thereafter subjecting the wool to a washing treatment with a dilute alkaline aqueous solution.

3. The improvement in the treatment of raw wool for the removal of foreign matter of vegetable origin which comprises subjecting-the wool to the action of dry hydrochloric acid gas at a moderately elevated temperature for a period of time insufficient to completely carbonize the foreign vegetable matter but sumcient to convert it to a dry friable state while excluding moisture table origin which comprises subjecting theA wool to the action of dry hydrochloric acid gas at a temperature not substantially exceeding 140 F. while excluding moisture therefrom, neutralizing the hydrochloric acid gas with anhydrous ammonia while continuing the exclusion of moisture, crushing and dusting the foreign vegetable matter frein the wool bers and thereafter subjecting the wool to a Washing treatment with a dilute alkaline aqueous solution.

5. The improvement in the treatment of raw wool for the removal of foreign matter of vegetable origin which comprises heating and drying the wool to reduce its normal moisture content, subjecting the wool to further drying in a moderately heated zone from which air and moisture are withdrawn to reduce the pressure to not more than about 1.5 inches of mercury absolute, supplying dry hydrochloric acid gas to said zone and intimately contacting the wool and acid gas for a substantial period of time while excluding moisture therefrom, and thereafter neutralizing the acid gas with anhydrous ammonia gas while continuing the exclusion of moisture.

6. The improvement in the treatment of raw wool for the removal of foreign matter of vegetable originwhich comprises heating and drying the Wool to reduce its normal moisture content. subjecting the wool to further drying in a moderately heated zone from which air and moisture are withdrawn to reduce the pressure to not more than about 1.5 inches of mercury absolute, supplying dry hydrochloric acid gas to said zone and intimately contacting the wool and acid gas therein for a substantial period of time at a moderately elevated temperature and under increased pressure while excluding moisture therefrom, and thereafter neutralizing the acid gas with anhydrous ammonia gas while continuing the exclusion of moisture.

'7. The improvementin the treatment of raw wool for the removal of foreign matter of vegetable origin which comprises heating and drying the raw wool to substantially dehydrate the raw wool, supplying the dehydrated wool while still in a heated condition to a moderately heated Lasarte,

carbonizing zone, evacuating the carbonizing zone to remove the air and any remaining moisture, supplying dry hydrochloric acid gas to the carbonizing zone and maintaining the dry wool in intimate contact therewith and at a moderate temperature for a period of time sufiicient to convert foreign vegetable matter to a dry friable state, neutralizing the hydrochloric acid gas with anhydrous ammonia gas while still excluding moisture from the carbonizing zone, subjecting the dryheated wool fibers to a crushing and dusting action to pulverize and remove the vegetable matter from the woolen fibers and thereafter washing the treated wool with a dilute aqueous alkaline solution.

d. The improvement in the treatment of raw wool for the removal of foreign matter of vege `dry friable state, neutralizing the hydrochloric acid gas with anhydrous ammonia gas While still excluding moisture from the carbonizing zone, subjecting the dry heated wool fibers toa crushing and dusting action to pulverize and remove the vegetable 4matter from the woolen iibers,

thereafter washing the treated wool with a dilute aqueous alkaline solution, subsequently subjecting the wool to a washing treatment with fresh water and finally drying the wool.

9.--The improvement in the treatment of raw wool for the removal of foreign matter of vegetable origin which comprises heating and drying the raw Wool to substantially dehydrate the raw wool, supplying the wool while Vstill in a dry heated condition to a moderately heated carbonizing zone, evacuating the carbonlzing zone to remove the air and remaining traces of moisture, supplying dry hydrochloric acid gas to the carbonizing chamber and maintaining the dry wool in intimate contact therewith for a period of time suillcient to convert foreign vegetable matter to a dry friable state, neutralizing the hydrochloric acid gas with anhydrous ammonia gas while still excluding moisture from the carbonizing zone, subjecting the dry heated wool fibers to a crushing and `dusting action to pulverize and remove the vegetable matter from the woolen fibers and thereafter washing the treated wool with a dilute aqueous solution of ammonia. l0. The Vimprovement in the treatment of raw wool for the removal of foreign matter of vegetable origin which comprises heating and drying the wool to reduce its normal moisturecontent, subjecting the dry wool at a moderately elevated temperature to the action of hydrochloric acid gas free from moistureand inert gaseous diluents for a period of time sufficient to convert the vegetable matter to a dry friable state, and thereafter neutralizing the acid gas with anhydrous ammonia gas while continuing the exclusion of moisture.

HOWARD D. GORDON.

WILLIAM W. GORDON. 

